Recently I had a chance to test the velocity of my 45-90. Sure did open my eyes to why I cannot stay on target at 800 yards. The spread went from 1306 to 1389 FPS. With in that spread there would be groups of rounds just one or two FPS off. Then wildly jump high or go lower. Pondering about what I can do to get a better extreme spread. First thing I am going for is bullet tension. After that I am at a loss. Primers might also be the trick. Sure would like some added thoughts. Some of the extreme speads that I have read about have been mightly low.

I would start with weighing a 'set' of cases from a single lot number. If they all weigh the same, they should have the same volume.
Then weigh your bullets. For this part of load development, I don't have a 'range' of acceptable weights. All bullets chosen will weigh exactly the same.
Then (of course) your powder charges must be individually weighed...and care taken to be sure every granule of powder ends up in the case, not stuck in the drop tube or something.

Consistent neck tension is required, or no neck tension at all. I choose 'none'.

After all rounds have been assembled, they should all weigh the same if the individual components did.

Finally, barrel condition must be the same for each shot. How you choose to do that is up to you, but wiping between shots seems like the most certain method.

I have seen ES and SD numbers less than 10 using only the measures above. There are other things which can be added...uniforming primer pockets, to name one.

Hold on your rifle will effect velocitys over a chornograph, what type of chronograph?. Fouling will be another effect. You didn't mention if you wipped or blowtubed. Were in your string of fire did velocitys change?

what brand of brass are you using ? Starline ? if so did you anneal the cases ? What brand of primers are you using ? How are you compressing the powder ? And what brand and granulation of powder are you using ? And of course, which bullet and lube ?

Wow! I guess I left a ton of information out that should have been included. Well I use Swiss 1.5 at 85 grains, cases are all preped, cases weighed no I have not done that. Starline brass that have been annealed. I do not use any compression on the powder, using a .060 poly wad. I have recovered some of my projectiles, hard to tell 100% but I don't see any problems to the base of the bullet. Oh! before I forget I am using a BACO Creedmore bullet. Cast from different blends of lead. All of this scrap lead comes out to 20-1 on a Seaco lead tester. I have tried just straight wheel weights. I did have at one time certified 20-1 lead but did not see any differences on the target. Bullets are within plus or minus one grain. Primers I have tried were CCI 200's, an old lot number about 15 years old gave me the best results on the target,velocity can't give a clue to that as I did not check. Winchester large rifle, CCI pistol, BR2's. But with all of the primers used, only the Winchester were run on a Chrony. A first edition unit. Thought about the weather condition but I did have an overcast sky. Now as for holding while shooting over the chrony never entered my mind. But will the next time.

Have been playing with this rifle for over a year first with paper patch. But would tumble starting at three hundred yards. No matter what I would do. So I had to switch to a grease groove. Thanks to all that replied. I will re-look over my whole reloading operation, and take better notes. This gun will shoot 34 inches or less at 800 yards or go bald thinking about it. Thanks once again to those that replied.

I have had some issues with the BACO creedmore bullet that I have. Casts a beautiful consistent bullet, but the grease grooves are slight different in geometry than say a Paul Jones creedmore or a Steve Brooks version of the PJC. I have 1 rifle that will shoot it and one that won't. The mould will throw bullets that are +- 3 or 4 tenths of a grain all day long.

With the smaller grease grooves that the BACO has, could you have some fouling issues ? What kind of lube are you using?

Have you tried it with a 540 gr Paul Jones Creedmore ?

Everyone is just hunting for the variable(s) that is could be causing the problem

Think I'ld be putting a wee bit of compression on that powder, or up the charge just a tad to get some compression.
Lead mining, are you sure you don't have some lead buried deep in a land somewhere?
Lube are you getting a lube star on the muzzle and if so, is it soft or hard?

Lube and fouling, the lube is a home made fomula that I gleened from the web site. 50% Olive Oil, 40%bees wax, 10% lanolin. I wipe after every round fired. Wiping solution is water soluble machine oil and distilled water. A 20% oil mixture. Leading, I have not seen any leading since I went to this lube. I clean the rifle after use with a .22 bore cleaning solution. Takes only minutes to clean. But I let it soak and at least the part of the following day, just to ensure I have no leading. The wet patches seem to have the same weight of push though out the length of the barrel. Well here is the actual velocities I shot. When started I did not want the barrel to change temps. I followed the normal routine of wiping. 1318 1322 1322 1309 1306 1353 1376 1393 1312 1306 1385 1306. A dozen rounds fired.

Now I have not read any negitive comment before today about the BACO Creedmoor bullet. Honesty thought I made a good choice. We will try the suggestion made. First item out of the gate will be neck/bullet tension. Making my own, now this is going to be a Rube Goldberg project.

I said I have 1 rifle that will shoot it and 1 that won't. The other comments were positive, about it being consistent, a good bullet etc. I just wish the lube grooves were a little bigger. That is all.

I have a shiloh 45-70 that will shoot it accurately and a CPA 45-70 that won't. The CPA exhibits the same kind of behavior you are getting. The CPA will put 5 540 gr PJC's into a silver dollar sized group at 200 yds if I do my part but I cannot keep the BACO creedmores on a chicken target at 235 yds with the CPA. I just haven't figured it out yet and may not mess with it in the CPA anymore. The Shiloh shoots just fine at all distances.

Some rifles just won't shoot a particular bullet no matter what you do, or how good a bullet mould it came out of etc. And there are just certain bullets that most rifles will shoot well no matter what. In my experience that is 540 gr PJC.

Make sure you have fresh batteries in that crono EACH time..........
What is your bbl twist?
Do you neck size of FL?
Up your load to 90grns.
What dia are your bullets.
Try some different bullets. Order some from BACO or Sagebrush.
Try .0015-.002" neck ten.
I'm having very good luck with 85grn FFF Goex and a PJ #45001 @ 30:1 shot as cast using DGL lube, in my .45-90 Shiloh #1, 30" bbl.
10 shots ave MV is 1322fps(4K', ASL)with ave ES of 10fps or less IF I do my part.
Respectfully,
LG

DRCook, My rifle is a CPA. Hey i did not mean that the BACO was down in the dirt junk, but more as constructive comment about its grease grooves. I know the chamber is a tad long 2.450 as best as I can mesures with a Goldberg tool I made. So I have taken 45-100 brass and cut them down to the 2.450 length. I will try another bullet after I do this last experiment with neck tension.

Lumpy Grits The twist rate is 1-18 Badger. Bullet drops from the mold at .459. have not tried neck sizing but have done a very light amount of crimp using the seating die. Not too good but it was another experiment to try. Hence out to the shop to make a crimping die. The 90 grains of powder I tried that. Made my flase teeth spin inside my mouth. Yes I need to get a sissy pad for that load. All I can remember from that load is it was punishing.

Ranch 13 Yes I do wipe with a dry patch. Now I cut my own patchs from 100% cotton flannel from the fabric shop. This has crossed my mind that the thickness of the material might not be up to par. Different patchs are on the way.

I am indebted to all those that have replied. AS you can read, I have thought of numerous different things. Those items that I have not tried will be done.

Have you checked the mainspring to make sure that it is adjusted tight enough. CPA's loosen up mainsprings every once in awhile and can cause erratic ignition. At least mine do. I have a couple of them. Also the buttstocks can loosen up, and also the set screw for the barrel can loosen up and cause erratic behavior.

I take teflon tape and wrap the threads so that you have to hand screw them in tight, you will have to play around with the proper nbr of wraps to get the barrel to screw all the way in. I also teflon tape the set screws so they don't loosen up. I get absolutely no wear on the barrel or reciever threads due to the teflon tape. I just use the thin white stuff so that the threads can cut it but still cause a tightening effect.

You probably ought to do a chamber cast. That is easy to do in a CPA with the removeable barrel.

Did you get lucky and get a tight chamber, so that maybe cut down 45-100 is not giving you enough spring for a clean release of the bullet ?

What length barrel do you have ? My 45-100 CPA has a 32" #5 profile. I also have a 32" #4 profile 45-100 that goes with the 45-70 rifle.

I have found that Fed 210M (match) primers work pretty dang well with the CPA rifles at least with mine they do. I pretty much use Fed 210M's for anything 45-70 and larger.

I have had the problem with the main spring. It has loosen up once again, the hammer will not set 100% of the time. You have me on the barrel and the set screw. I did not think of that! Today busy making the die for the neck tension. A good friend of mine who is a top notch machinest came by to check on how I was progressing. His best words of encouragement was I should open a comdey show. So much for my machinst ability. Gave me a few pointers and I am on my way to completing the project. Did manage to slip into the loading room and re-doing my cases. Found some as much as .010 off. So all the cases are getting there turn in the trim die. One thing else I learned today was to trim the cases twice. File the cases to the limit of the die. Removed, wiped the lube off, deburred, and measured. 3-4 thousandths off. Re-insert back into the trim die and file. This second filing gets them to the exact size I am looking for. Dave you mentioed the spring back of the 45-100 cases. Great point, that idea is one of a couple thougts brought up about cases in this blog. The case that were found to be long would not accept a bullet. The OAL of the cases that were below 2.450 would accept a .459 bullet. So hopefully I will not out think myself, and get this rifle to shoot as I suspect it will. Oh yes before I forget the fired cases mike out .482 OD at the mouth. Makes the case wall thickness .013 or there abouts.